Nail polish brush



FIG. 1 is a front, right and top perspective view of a nail polish brush showing my new design;

FIG. 2 is a front, right and bottom perspective thereof;

FIG. 3 is a perspective view thereof in the combined state;

FIG. 4 is a front side view thereof;

FIG. 5 is a rear side view thereof;

FIG. 6 is a left side view thereof;

FIG. 7 is a right side view thereof;

FIG. 8 is a top plan view thereof; and,

FIG. 9 is a bottom plan view thereof.

The broken lines in the figures illustrate portions of the nail polish brush that form no part of the claimed design. 

CLAIM The ornamental design for a nail polish brush, as shown and described. 